Molten metal handling

ABSTRACT

Parts of metal handling apparatus which are adapted to be relatively movable tend to be hindered in such movement by the solidification of molten metal in contact therewith. To avoid this, prior to pouring molten metal into the apparatus, there are located at positions in the apparatus where such solidification would cause such hindrance, shapes of bonded fibrous material which are adapted to be burnt, melted or softened at the temperature of the molten metal.

United states Patent lnventor John David Sharp Nechells. England Appl. No. 826,513 Filed May 2], 1969 Patented June 22, 1971 Assignee Foseco International Limited Priority May 21, 1968 Great Britain 24193/68 MOLTEN METAL HANDLING 4 Claims, 1 Drawing Fig.

US. Cl 222/559, I 222/563 Int. Cl 867d 3/00 Field ofSearch 266/38, 39, 42; 239/265.l5; 164/335; 137/375; 251/332; 222/559 [56] References Cited UNITED STATES PATENTS 2,883,722 4/1959 Bidner 222/559 3,124,854 3/1964 Dore 22/84 3,494,826 2/1970 Scheiber 162/168 Primary Examiner-Robert B. Reeves Assistant Examiner-John P. Shannon, Jr. Attorney-Wolfe, Hubbard, Voit and Osann ABSTRACT: Parts of metal handling apparatus which are adapted to be relatively movable tend to be hindered in such movement by the solidification of molten metal in contact therewith. To avoid this, prior to pouring molten metal into the apparatus, there are located at positions in the apparatus where such solidification would cause such hindrance, shapes of bonded fibrous material which are adapted to be burnt, melted or softened at the temperature of the molten metal.

PATENTEnJuNzzlsn Bl-586,218

INVENTOR. JOHN DAVID SHARP- BY:- afaw mzw (9M.

ATTORNEYS MOLTEN METAL HANDLING This invention relates to molten metal handling apparatus, particularly to ladles.

In the handling of molten metal, metal is often poured from one container, e.g. a furnace, into another, whence it is poured, for example, into ingot or casting moulds. Generally, I

the vessel into which molten metal is poured is not at the temperature of the molten metal. As a result, the first metal to impinge upon the inner surfaces of the vessel will solidify thereupon. If such a surface is in direct contact, when the vessel is full, with the body of molten metal held therein, the heat of that body of molten metal will be sufficient to remelt at least some of the solidified metal. However, in places where the solidified metal is not in such great thermal contact with the molten metal, such as a crack in the lining of the vessel, the solidified metal tends to remain solidified.

In the corners of metal containing vessels, and in cracks in the walls thereof this phenomenon is of no great moment, and indeed the metal tends to fill up the inner surface of such vessels and prevent the formation of irregularities. However, in the case of vessels which have within them any mechanism, such as a stopper or a stirrer, the irregularities near such mechanism tend to become filled with solidified metal, and the efficiency of that mechanism is thus impaired.

This disadvantage is particularly severe in the case of metal ladles. Such ladies are used for pouring molten metal into a set of, for example, ingot moulds. The ladle is moved over each ingot mould successively or a cluster of bottom poured molds and the required amount of molten metal run from the ladle. The flow of molten metal is controlled by a Stopper rod, adapted to engage in an aperture in the base of the metal ladle. The stopper rod is usually made of steel covered with a refractory material which, at the temperature of the molten metal, may be soft compared to the hardness of the refractory ring into which the stopper rod fits. For certain ladle/stopper rod assemblies both the stopper rod and nozzle are made of equally hard refractory materials. in order to help location of the stopper rod, the inside of the refractory ring is generally bell shaped. When the molten metal is first poured into the ladle, metal falls into the thin gap between the outer wall of the stopper rod and the inner walls of the refractory ring, and solidifies there. This solidified ring of metal sometimes makes the stopper rod extremely difficult to withdraw. Once, however, such a withdrawal has taken place, the solidified ring is melted and carried away by the stream of molten metal leaving the ladle, and when the stopper rod is used to close the ladle pouring aperture, no further freezing takes place. Similarly with any other pieces of mechanism which are surrounded by molten metal, once the mechanism has been operated, there is no danger of solidifying material hindering its operation. The present invention provides a method of overcoming this difficulty.

A method for reducing the tendency of parts of a metal handling apparatus which are adapted to be relatively movable, to be hindered in such movement by the solidification of molten metal therein or thereon, which comprises prior to pouring molten metal into the apparatus, locating at positions in the apparatus where such solidification would cause such hindrance, shapes of bonded fibrous material which are adapted to be burnt, melted or softened at the temperature of the molten metal. The material may be cellulosic or of comparatively high melting point inorganic fibers, the melting or softening point of which is below the temperature of the molten metal.

Once the mechanism is set in action the shape of bonded fibrous material, now burnt out, melted or softened under the action of the heat of the molten metal, disintegrates and lets the molten metal flow into the irregularities while the mechanism is in motion. Thus, the solidification of molten metal in the irregularities is minimized.

The invention is illustrated in the accompanying drawing which shows a sectional view through the floor and stopper of a metal handlin ladle.

Referring to t IS drawing, the ladle consists ofa metal vessel 1 lined with refractory bricks 2. Set in an aperture in the floor of vessel 1 is a refractory nozzle 3 having a conical upper opening 4 into which a stopper rod 5 fits. The stopper rod 5 is made up of a central metal rod 6 and a number of refractory sleeves 7 ranged thereon.

Generally, if molten metal is poured into such a ladle, metal tends to solidify forming a ring at 8 which sticks the stopper rod 5 to the base of the ladle. By the provision, around the rod 5, of a'bonded fibrous sleeve 9, shown by dotted lines, molten metal is prevented from penetrating to the locations 8. When the stopper rod is first lifted, the stream of molten metal rapidly sweeps away the burnt-out sleeve 9.

The metal of the present invention is of particular value in connection with the modified ladle stopper assembly described in our copending Pat. application No. 55267/66.

The following Example illustrates a further type of fibrous sleeve which may be employed asjust noted.

EXAMPLE A slurry was made up from:

Wood fiber 1 percent by weight Slag wool l percent by weight Sodium silicate solution (48% solids) 18 percent by weight Water percent by weight This slurry was dewatered at low pressure onto a perforated cylindrical former to deposit a sleeve of wall thickness approximately three-quarters inch. After oven drying, the sleeve had an approximate composition of:

Wood fiber 47 percent by weight Slag wool 47 percent by weight Sodium silicate 6 percent by weight The sleeve was manufactured with an internal diameter approximately 2 mm. smaller than the stopper rod diameter. During fitting to the stopper rod, the fibrous sleeve was compressed slightly to give a tight fit. In use, the sleeve slowly carbonized and disintegrated so that the purpose of temporarily sealing the surrounding area of the tapping hole was fulfilled.

Other inorganic fibrous materials which are normally considered to be refractory may be used in place of the slag wool just noted since they do melt under sustained contact with molten steel. Such materials are the calcium and aluminum silicate fibers.

Other binding agents which may be used in the sleeve include natural and synthetic resins (e.g. ureaand phenol-formaldehyde resins, furane resins, polyurethane resins) gums, and sulfite lye.

I claim as my invention:

1. A method for reducing the tendency of pairs of a metal handling apparatus which are relatively movable to be hindered in such movement by the solidification of molten metal in contact therewith, which comprises, prior to pouring molten metal into the apparatus, locating at positions in the apparatus where such solidification would cause such hindrance, shapes of bonded fibrous material including at least some 'cellulosic fibrous material, which shapes at the temperature of the molten metal burn, melt, or soften.

2. A method according to claim 1 wherein all the fibrous material is cellulosic fiber.

3. A method according to claim 1 wherein the fibrous material is a mixture of cellulosic fibrous material and an inorganic fiber selected from the class consisting of calcium silicate fiber, aluminum silicate fiber and slag wool.

4. A method according to claim 1 wherein the fibrous material is bonded with a binding agent selected from the class consisting of ureaand phenol-formaldehyde resins, furane resins, polyurethane resins, natural and synthetic gums and sulfite lye. 

2. A method according to claim 1 wherein all the fibrous material is cellulosic fiber.
 3. A method according to claim 1 wherein the fibrous material is a mixture of cellulosic fibrous material and an inorganic fiber selected from the class consisting of calcium silicate fiber, aluminum silicate fiber and slag wool.
 4. A method according to claim 1 wherein the fibrous material is bonded with a binding agent selected from the class consisting of urea- and phenol-formaldehyde resins, furane resins, polyurethane resins, natural and synthetic gums and sulfite lye. 